Combining Transmission Level Power at Distribution Level Voltages with
Fault Current Management to Enhance the Safety, Security and
Load Serving Capability of Urban Electric Grids.
A white paper by AMSC®, September 2014
Executive Summary
Increasingly intense weather events, terrorist threats, and aging infrastructure… These are all challenges that the world is facing today. These challenges represent significant threats to the electric grid, which is fundamental to our way of life. Without reliable power, basic human needs, such as food, clean water, and protection from the elements would quickly become a challenge. The economy would grind to a halt without access to fuel, banks, and the Internet.
In short, a reliable and resilient electric grid is central to our safety, security, and economy.
Consider just a handful of recent events:
• Weather: When Hurricane Sandy swept ashore in October 2012,
8 million utility customers along the Eastern Seaboard, including major centers of economy, were without power for days and weeks and fuel distribution networks were paralyzed.1 The White
House has estimated that power outages caused by severe weather between 2003 and 2012 cost the United States economy somewhere between $18 and $33 billion.2
• Equipment Failure: In March 2012, an event at a substation in
Boston caused a fire and a two day blackout in one of the city’s busiest residential and commercial neighborhoods. Equipment failure caused similar outages at the same substation again in May
2012 and in June 2013.3
• Terrorism: In April 2013, snipers opened fire on a substation in
Silicon Valley. The former chairman of the Federal Energy
Regulatory Commission (FERC) called the attack the most significant incident of domestic terrorism involving the grid that
has ever occurred. In fact, the former chairman believes that if a surprisingly small number of substations were knocked out at once, the entire system could be destabilized enough to cause a blackout that could encompass most the United States.4 Terrorist organizations around the globe were linked to 2,500 attacks on transmission lines or towers and at least 500 substations from
1996 to 2006.5
• Cyber Security: Beyond physical attacks, cyber attacks could take down the grid by disabling internet communications and important pieces of equipment. According to a Wall Street
Journal analysis of emergency reports that utilities file with the federal government, 13 cyber incidents have occurred in the past three years.6
Beyond providing resiliency during calamitous events, urban utilities are also challenged with population growth. The population in
“urbanized areas”7 is growing at a faster rate (14.3% from 2000 to
2010) than the overall population growth (9.7% from 2000 to
2010).8 In fact, 71.2% of the U.S. population now lives in urbanized areas. There are strong efforts underway to improve efficiency and add distributed generation where possible, however, this is likely not enough. Increasing load creates a substantial challenge for urban utilities. Adding facilities and equipment is more expensive in the urban environment because of the higher cost of land. Additionally, in the urban environment, reliability requirements are more strict and operating requirements, such as noise, safety, footprint, and access are more difficult.
The REG System
AMSC’s Resilient Electric Grid system is designed to interconnect critical urban substations, enabling them to share transmission connections and excess station capacity, while controlling the high fault currents that naturally result from such connections. By enabling the sharing of assets, urban utilities can “keep the lights on” and ensure the safety and security of residents following calamitous events. Additionally, interconnecting substations can enable utilities to increase the load serving capacity of existing substation equipment.
Many times, current urban substation design provides for
